A total of 15 studies were found utilizing medical and surgical treatments for AKN (see Tables 1, 2). Medical management included the use of topical or oral antibiotics, corticosteroids, retinoids, topical fusidic acid and topical urea. Medical management showed varying degrees of improvement, with complete resolution in one case. Overall, surgical approaches to treating AKN resulted in a drastic improvement of the condition, though there was some recurrence of disease and the cosmetic results were variable. Additionally, there was one report on radiotherapy and dermabrasion.
The earliest case of medical management of AKN was reported by Dinehart et al.  who treated two females with intralesional triamcinolone and tetracycline (oral), respectively. There was marked improvement in both patients. The patient receiving triamcinolone had no new lesions at 6 months, though many small papules remained; the patient receiving tetracycline had dramatic improvement, including a decrease in pain, size and purulence of the lesions. Conversely, Harris et al.  reported a case of AKN in a male professional football player. Triamcinolone and antibiotics were administered with little improvement seen until the patient’s offseason, at which time the condition spontaneously resolved. Medical management has also been a suitable therapeutic approach for AKN associated with keratosis follicularis spinulosa decalvans [14, 18]. Two cases have been reported, both involving young men (aged 18 and 27 years, respectively). Goh et al.  utilized oral isotretinoin (20 mg, 0.25 mg/kg/day) after failed attempts with minocycline (oral), doxycycline (oral), mometasone furoate (topical) and triamcinolone acetate (intralesional injection). Within weeks, dramatic improvement was seen in the lesions on the vertex of the patient’s scalp. Inflammation on the neck responded less dramatically, while the patient’s follicular tufting/follicular hyperkeratotic papules exhibited no change. Maintenance on low dose isotretinoin (20 mg every 2–3 days) kept the patients vertex inflammation under control, seen at 1-year follow-up. Janjua et al.  used combination topical fusidic acid and oral cefadroxil (500 mg twice daily for 2 weeks) to treat a patient. Antibacterial therapy was repeated as necessary. There was marked improvement in the lesions of the scalp and nuchal area at 6 months, though some hypertrophic scarring and tufts remained. Overall, medical management seemed to improve the condition, though complete resolution was not seen. Thus, the modality may be reserved for mild cases of AKN.
Surgical excision was described in eight studies [4, 19–25]. In one report, six males with AKN refractory to numerous medications, both topical and systemic, underwent surgical excision of the involved areas to muscle fascia or deep subcutaneous tissue . Healing by second intention was allowed, which resulted in an average closure time of 6–8 weeks. Good cosmetic results were achieved in four patients (those receiving horizontal elliptical excision including the posterior hairline), while recurrence occurred in two patients. Another study reported surgical excision and healing by second intention performed on five patients . Although scarring was significant, the cosmetic results were acceptable in all patients. At 2 months to 4 years follow-up, contractures did not limit function nor did disease recur. In two similar studies by Bajaj et al.  and Etzkorn et al. , a total of three cases of AKN were surgically excised with healing by second intention. Excellent cosmetic results and no recurrences were seen (follow-up at 7, 14 and 18 months, respectively).
Electrosurgery is another treatment option for AKN. This modality allows for excision of the lesion with simultaneous coagulation of small vessels similar to laser excision with CO2. In one case utilizing electrosurgery, healing by second intention resulted in complete closure at 5 weeks with good wound contracture and a small flat scar . No recurrence was observed at 8 months postoperative. In the largest study to date, Gloster et al.  performed surgical excision in 25 patients with AKN. Twenty patients underwent excision with layered closure in 1 stage, 4 underwent 2-stage excision with layered closure and one underwent excision with second-intention healing. Treated areas were subjectively scored from poor (1) to excellent (4) by both the patient and physician. At 1-year follow-up, the results were scored with an average overall score of 3.8. Five patients, however, developed hypertrophic scarring and 15 patients had mild recurrences of tiny pustules and papules during the first 4 months that were subsequently treated with topical and intralesional steroids.
An alternative surgical approach was taken in a case of AKN in a 40-year-old male using a semilunar 400-ml tissue expander . Postoperative infiltrations were performed at 14 days and each week thereafter, expanding the tissue by 380 ml. At the 46th post-operative day, the expander was removed and the affected area was closed. Local radiotherapy was administered weekly until 1000 rad was reached. An excellent cosmetic result was achieved, with no recurrence of AKN and no signs of the “stretch-back” phenomenon at 2-year follow-up. The case was complicated by infection at 20 days post-operation that was successfully treated with cephalexin.
A variety of combined treatments have also been reported for the treatment of AKN. Layton et al.  compared intralesional triamcinolone with cryosurgery using the spot freeze technique with two 15-s freeze–thaw cycles. Overall, the assigned scores of pre-therapy palpability (used as an indicator of severity) correlated with the response to treatment (P < 0.04) and cryosurgery provided better results for more vascular lesions (P < 0.03). At 8-week follow-up, there were sustained improvements in the lesions. Dermabrasion was attempted in one case of AKN in a 38-year-old male . After three sessions, there was approximately a 50% reduction in lesion size. However, the patient refused additional sessions and was subsequently referred for surgical excision. In one particularly refractory case of AKN reported by Cayetano et al. , the patient was treated for 5 years with cycles of cryotherapy, topical antibiotics (clindamycin 1% solution), oral antibiotics (doxycycline 100 mg/day), infiltrations of intralesional triamcinolone, oral isotretinoin (50 mg/day) and oral sulphone (100 mg/day). The patient also received electro-curettage and partial excision with primary closure. With continued worsening, the patient underwent radiotherapy at 3 Gy per session for ten sessions on alternating days (total dose of 30 Gy). Complete alopecia was seen at 2 months after radiotherapy which resolved 4 months later, except in the area of the original keloid plaque. The lesion eventually flattened, leading to a small residual scar and good cosmetic results. No recurrence was seen at 20-months follow-up.
Light and Laser Therapy
Lasers utilized included the CO2 laser, 1064-nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, 59-nm pulse dye laser (PDL), and 810-nm diode laser (Table 3). The earliest study by Kantor et al. used a CO2 laser for surgical excision for late stage treatment of AKN . By using a CO2 laser with a focused beam, fibrotic areas in six black patients and two white patients could be removed in an outpatient-based setting with local anesthesia. Moreover, none of the patients who were treated using this modalityhad a relapse. Two patients in the study with early AKN were treated with laser evaporation using the unfocused beam setting with 130–150 J/cm2 fluence with three to four passes in one session. However, relapse occurred in both cases. In another case, CO2 laser evaporation with the same fluence setting was utilized in a Caucasian male who had developed AKN while on chronic cyclosporine treatment for a heart transplant. The patient’s AKN relapsed shortly after treatment forcing the patient to undergo surgical intervention . In a third case involving a Caucasian male, CO2 laser excision was coupled with a single postoperative intralesional injection of triamcinolone acetate (5 ml of 25 mg/ml) and three radiotherapy sessions of 400 cGY . The first of which was given on the same day following the procedure. The patient developed a few satellite lesions that were treated with CO2 laser excision. The patient had a full recovery and regrowth of hair in the treated region.
In a case series by Shah , 2 males were treated using a 810-nm diode laser who had previous treatment failures with oral antibiotics, intralesional and topical steroids. After 4 treatment sessions of 23–26 J/cm2 fluence with 100 ms pulses, the patients had a 90% and 95% clearance, respectively, that was maintained at 6-months follow-up. Treatments were tolerated with only transient mild burning.
Dragoni et al.  treated a single fair-skinned 23-year-old Caucasian male using a 595-nm PDL with 6.5 J/cm2 fluence and 0.5 ms pulse. The results, however, were transient and lesions returned in 1 month. Subsequently, a 1064-nm Nd:YAG laser with 101–120 J/cm2 fluence was used for four sessions, which lead to a significant improvement in scarring that was clinically apparent. Esmat et al.  also used a 1064-nm Nd:YAG laser to treat patients with AKN in a pilot study using 35–45 J/cm2 fluence over five sessions. Patients between the ages of 22 and 54 years old with Fitzpatrick skin types 3 and 4 were treated. Significant improvements were seen after the third treatment and in 82% of the lesions after the 5th session. Moreover, biopsies taken from the treated area showed significant reductions in the inflammatory infiltrate after the final treatment. No recurrences of lesions were noted at 1-year follow-up.
Light therapy consisted of the use of a 290- to 320-nm targeted UVB (tUVB) halide arc lamp (Table 3). The most recent study by Okoye et al.  used tUVB light to treat 11 male patients using a split-scalp designed study. Initial UVB dosage was determined using the minimal erythema dose that ranged between 0.23 and 0.48 J/cm2. Treatment dosing was increased by 20% per week until the end of 8 weeks and was maintained at the same dose for an additional 8 weeks. The control side of the scalp was treated after the 8th week according to the same protocol until the end of the study at 16 weeks. Treatments were tolerated well with only mild burning and erythema. Patients were given two to three treatments per week. A significant improvement was noted on the treated side by 34% at 8 weeks and 49% at 16 weeks. The results were maintained at 2-months follow-up. In addition to clinical improvements, an up-regulation of matrix metalloproteinases MMP1, MMP9, TGFB1 and COL1A1 were seen by histology, indicating higher rates of extracellular matrix turnover.